The proposed pilot study addresses NIA PAR 02-049, Research Objective 24, Improved Measures and Methodologies, by evaluating the utility of the multilevel modeling (MLM) approach to examine the well-being of the Care Receiver (CR)-Caregiver (CG) dyad over a 20-month period. The goal of this proposed pilot research is to reconcile changes over time in two subjective measures of well-being (i.e., mutuality) - one from frail CRs and the other from CGs. MLM is an innovative methodology, which reconciles two observed measures into four latent outcomes for each dyad: a dyad score, a dyad discrepancy score, and a true score for both CR and CG, adjusted for measurement error. Thus, in contrast to standard approaches to caregiving research that focus on the individual CR and CG as units of analysis, the proposed study focuses on the dyad as the unit of analysis. A secondary goal of the study is to examine the relationships between changes in the latent dyad outcomes and changes in physical and mental well-being of both CR and CG. The proposed pilot study is a longitudinal 20-month (5-wave), secondary-data analysis of CRs and CGs from the study PREP: Family-based Care for Frail Older Persons (R01 AG17909, P. Archbold PI), known as the Family Care Study. The Family Care Study is a randomized nursing intervention trial, which follows families three times during a 12-month intervention period, and on two subsequent occasions. The aims of the proposed study are: 1. To describe dyad mutuality and dyad discrepancy for both intervention and control groups at baseline. 2. To describe the pattern of change in average dyad mutuality and dyad discrepancy over 20 months. 3. To describe the pattern of change in true score mutuality (for CRs and for CGs) over 20 months. 4. To describe the effect of the intervention on changes in dyad mutuality, dyad discrepancy, and true scores. Analyses will involve MLM (both univariate and multivariate models). Findings from this methodological case study will provide the foundation necessary to seek funding for a more comprehensive longitudinal study of the CR-CG dyad (as the unit of analysis) to plan future dyadic interventions that strive for a balance between CR and CG needs and the physical and mental well-being of the dyad.